Electric de-icing device for turbojet engine nacelle element

ABSTRACT

The present disclosure provides an electric de-icing/anti-icing device for a turbojet engine or turbo-prop nacelle element to be protected from icing. The device includes: a heating assembly including first and second heating stages positioned in the nacelle element; an electricity supply circuit delivering a primary voltage to the first heating stage of the heating assembly. In particular, the electricity supply circuit includes an electricity source, and a de-icing/anti-icing circuit which is connected to the heating assembly and supplied voltage by the electricity source. Furthermore, the de-icing/anti-icing device includes components to supply a complementary voltage to the second heating stage of the heating assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No. PCT/FR2014/050016, filed on Jan. 7, 2014, which claims the benefit of FR 13/50115, filed on Jan. 7, 2013. The disclosures of the above applications are incorporated herein by reference.

FIELD

The present disclosure relates to an electric de-icing/anti-icing device in particular for nacelle air inlet lip for aircraft turbojet engine/turboprop, and to a method of de-icing/anti-icing of a nacelle element and of an aircraft element.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

An airplane is propelled by one or several propulsion assemblies each comprising a turbojet engine/turboprop housed in a tubular nacelle. Each propulsion assembly is fastened to the airplane by a mast generally located under a wing or at the fuselage.

A nacelle generally has a structure comprising an air inlet upstream of the engine, a median section surrounding a turbojet engine fan, a downstream section accommodating thrust reversal means and surrounding the combustion chamber of the turbojet engine, and is generally ended by an ejection nozzle the outlet of which is located downstream of the turbojet engine.

The air inlet comprises, on the one hand, an air inlet lip adapted to allow the uptake towards the turbojet engine of the air necessary for the supply of the fan and of the inner compressors of the turbojet engine, and on the other hand, a downstream structure on which the lip is added and to channel the air towards the fan blades. The assembly is fastened upstream of a fan casing belonging to the upstream section of the nacelle.

During flight, according to the conditions of temperature and humidity, frost may form on the nacelle, in particular at the outer surface of the air inlet lip. The presence of ice or frost modifies the aerodynamic properties of the air inlet and disturbs the flowing of the air towards the fan. In addition, the formation of frost on the air inlet of the nacelle and ice ingestion by the engine in case of ice blocks detaching can damage the engine, and pose a risk to the safety of the flight.

A solution for de-icing the outer surface consists in preventing ice from forming on this outer surface by maintaining the concerned surface at a sufficient temperature.

Thus, it is known, for example from U.S. Pat. No. 4,688,757, to collect the hot air at the turbojet engine compressor and bring it at the air inlet lip in order to heat the walls.

However, such a device requires a hot air intake duct system between the turbojet engine and the air inlet, as well as a hot air discharge system at the air inlet lip. This increases the mass of the propulsion assembly, which is not desirable.

In order to lighten to the structures used in the nacelles, more generally aeronautical equipment, it is common to use composite materials.

The use of these materials, in particular for producing the air inlet lip of the nacelle, is generally incompatible with the aforementioned pneumatic de-icing and anti-icing devices.

In fact, the exposure temperature of these materials must generally not exceed a critical threshold to avoid the denaturation of the material and hence damage to the structure.

These drawbacks have been overcome in particular thanks to electric de-icing/anti-icing systems.

The document EP 1 495 963 can in particular be cited although many other documents relate to the electric de-icing and its developments.

The implementation of an electric de-icing device uses heating resistance assemblies, also called heating mats, implanted at the air inlet lip near the outer surface and electrically supplied by an electric power supply source.

The European patent application EP 1 953 085 also relates to an electric architecture used for supplying heating mats.

The architectures described in this application provide an electric power supply source derived from a generator dedicated to the assembly of heating mats.

These architectures allow regulating the temperature in different areas of the air inlet of the nacelle. However, these de-icing systems are complex, heavy in terms of mass, reliability and availability.

SUMMARY

The present disclosure provides a de-icing device which is easy to set up, inexpensive, does not damage the composite materials, and is highly reliable and has a high availability.

The present disclosure provides an electric de-icing/anti-icing device for turbojet engine/turboprop nacelle element, comprising:

a heating assembly comprising two heating stages disposed in the nacelle element to be protected from frost;

an electric energy power supply circuit delivering a principal voltage to the first stage of the heating assembly, and the electric energy power supply circuit comprising:

an electric power supply source, and

a de-icing/anti-icing circuit connected to the heating assembly and supplied with voltage by said electric power supply source;

the de-icing device being characterized in that it further comprises means for delivering a complementary voltage to the second stage of the heating assembly.

Thus, by providing means for delivering a complementary voltage of the principal voltage to the second heating stage, the second stage is only supplied during particular phases of a flight, thus allowing to reduce the energy consumption of the heating assembly considerably. By way of example, the second heating stage may be supplied with voltage during the ascent or the descent phases of the airplane. Furthermore, the second stage constitutes an additional safety in case of malfunction of the first stage.

In addition, the single electric circuit allows the supply in electric energy of the heating assembly, thus also simplifying the electric network architecture for the heating element.

According to the present disclosure, the means for delivering said complementary voltage further comprise:

at least one temperature sensor positioned in the nacelle element to be protected from frost;

at least one contactor integrated to the de-icing circuit and in addition connected at the inlet to the electric power supply source and at the outlet to the second heating stage of the heating assembly;

at least one control unit connected to the temperature sensors and to the contactor, adapted to alternatively control the passage of the contactor between an inhibited position according to which the second stage is not supplied with voltage and a closed position according to which the second stage is supplied with voltage.

In one form, the control unit is integrated to the de-icing circuit, which allows providing a de-icing device which is compact and is easy to integrate.

According to a first form of the de-icing device according to the present disclosure, the electric power supply source is delivered by an airplane electric network.

According to this form, the de-icing circuit comprises:

a power conversion stage supplied with voltage by the airplane electric network and connected to the control unit, said power conversion stage being adapted to convert the alternating voltage delivered by the airplane electric network to variable direct voltage;

a contactor the inlet of which is connected to the outlet of the power conversion stage and the outlet is connected to the second heating stage the heating assembly, said contactor being controlled by the control unit.

According to a second form of the de-icing device according to the present disclosure, the electric power supply source is constituted by an electric generator.

According to this form, the electric generator is further connected to the first stage of the heating assembly, and the de-icing/anti-icing circuit is constituted by a contactor the inlet of which is connected to said electric generator and the outlet is connected to the second heating stage of the heating assembly, said contactor being controlled by the control unit.

Furthermore, the heating assembly comprises four heaters distributed on the periphery of the nacelle element to be protected from frost.

The present disclosure also relates to a nacelle for a turbojet engine or a turboprop comprising a de-icing/anti-icing device according to the present disclosure, characterized in that the heating assembly is integrated to an air inlet lip of said nacelle.

The present disclosure also relates to a method of de-icing/anti-icing of a nacelle element for turbojet engine/turboprop, said nacelle comprising a de-icing/anti-icing device according to the present disclosure, the method being characterized in that it comprises the following steps:

identifying the temperature of a nacelle element;

delivering to the first stage of the heating assembly a variable principal voltage according to the identified temperature; and

delivering to the second stage of the heating assembly a complementary voltage if the temperature value of the nacelle element to be protected from frost is lower than a predetermined temperature value.

Finally, the present disclosure relates to a de-icing/anti-icing method of an aircraft element, said element comprising a de-icing/anti-icing device according to the present disclosure, characterized in that it comprises the following steps:

identifying the temperature of an element of the component;

delivering to the first stage of the heating assembly a variable principal voltage according to the identified temperature;

delivering to the second stage of the heating assembly a complementary voltage if the temperature value of the aircraft element to be protected from frost is lower than a predetermined temperature value.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

Other features and advantages of the present disclosure will become apparent upon reading the following description and upon the examination of the accompanying figures, in which:

FIG. 1 schematically illustrates in cross section a nacelle air inlet lip for turbojet engine equipped with a heating assembly;

FIG. 2 schematically illustrates in cross section a heating assembly of the de-icing device;

FIG. 3 represents a first form of the de-icing device according to the present disclosure;

FIG. 4 represents in detail the de-icing circuit of the de-icing device according to the first form;

FIG. 5 is an illustration of a second form of the de-icing device; and

FIG. 6 illustrates in detail the de-icing circuit of the de-icing device according to the second form.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

Furthermore, the terms “upstream” and “downstream” are defined with reference to the flowing direction of the air flow in the nacelle in direct jet operation, the upstream of the nacelle corresponding to a portion of the nacelle by which the flow enters, and the downstream corresponding to an ejection area of said air flow.

Furthermore, “de-icing/anti-icing device” means any assembly adapted to allow de-icing or to prevent the formation of frost.

Referring to FIG. 1, schematically illustrating in cross section a nacelle air inlet lip for turbojet engine equipped with a heating assembly 1 comprising four heaters of identical design 3 a, 3 b, 3 c, 3 d distributed on the periphery of the nacelle air inlet lip, respectively “at 3 o'clock,” “at 6 o'clock”, “at 9 o'clock” and “at 12 o'clock”.

The heating assembly is mainly intended to be integrated to a composite, monolithic or sandwich air inlet lip, of a turbojet engine nacelle. Of course, the heating assembly may also equip other areas of the nacelle or other areas of the aircraft. In addition, such an assembly is not solely limited for application in the aeronautics field.

Referring to FIG. 2 representing a heater 3 a in cross section, such a heater comprises two heating stages 5 and 7 forming superimposed layers in the thickness of the heater. More specifically, once mounted in a nacelle or aircraft element to be protected from frost, the heating stage 5 covers the areas of the element to be protected from frost which are nearest to air flow areas, while the heating stage 7, superimposed to the heating stage 5, is farther away from the areas in contact with the air which flows. In a known manner, the heating stages are produced from an electrically conductive metal material.

Each heating stage 5, 7 is topped on either side of an electric insulator 9 typically fixed on the heating stages by adhesive means such as glue. As for the insulating elements 9 they are produced for example from a glass ply.

Of course, the resistive elements and insulating elements may be respectively produced from any other electrically conductive and insulating material.

Each heating stage 5, 7 of the heating assembly is supplied with electric energy by means of a single electric power supply circuit (not represented on this figure).

The electric energy power supply circuit comprises an electric power supply source supplying with voltage a de-icing (or an anti-icing) circuit connected to the heating assembly.

According to a first form represented on FIGS. 3 and 4, the electric energy power supply circuit comprises an electric power supply source constituted by the three-phase network 11 of the airplane, typically delivering alternating voltage, directly connected to the inlet of a de-icing/anti-icing circuit 13 (also called “NAI” for “Nacelle Anti Icing”).

The de-icing/anti-icing circuit 13 receives at the output cables 15, 17, respectively supplying with voltage the first and the second heating stages of the heating assembly.

The de-icing/anti-icing circuit 13 comprises according to the present disclosure a power conversion stage 19 comprising two redundant switching cells 21, 23, each being adapted for converting the alternating voltage delivered by the electric network of the airplane to a variable direct voltage.

The cells 21 and 23 are connected to a control unit 25, which activates either one of said cells according to their availability.

The control unit 25 is further connected to temperature sensors 27 a, 27 b, 27 c, 27 d, each being respectively placed in each heater 3 a, 3 b, 3 c, 3 d.

The de-icing/anti-icing circuit 13 comprises a contactor 29 of which the inlet is connected to the outlet of the power conversion stage 19. At the outlet of the contactor 29 the cable 17 is provided in connection with the second heating stage 7.

The contactor 29 is further connected to the control unit 25, which controls the alternative passage of the contactor 29 between a closed position and an inhibited position, as detailed hereinafter.

By way of example, the contactor 29 may be constituted of an electric or electromechanical switch.

The operation of the de-icing device according to the first form of the present disclosure will now be described.

The airplane electric network 11 supplies the de-icing/anti-icing circuit 13 with alternating voltage.

The power conversion stage 19, constituted by the redundant switching cells 21, 23, provides the conversion of the alternating voltage delivered by the electric network 11 into a variable voltage.

The control unit 25 chooses to actuate either one of the switching cells 21, 23 according to their availability.

Furthermore, the temperature sensors 27 a, 27 b, 27 c, 27 d return the temperature values identified at each heater 3 a, 3 b, 3 c, 3 d to the control unit 25.

The control unit 25 hence adapts the value of the output voltage supplying the first heating stage 5, called principal voltage, so as to maintain the temperature of the lip constant regardless of the outer climatic conditions.

The contactor 29 is in an inhibited position, a position according to which no voltage is delivered to the second stage 7 of the heating assembly.

When the voltage delivered in the outlet of the de-icing/anti-icing circuit 13 is insufficient for maintaining the temperature of the nacelle air inlet lip constant, the temperature sensor informs the control unit 25, which activates the passage of the contactor 29 from the inhibited position thereof to a closed position, a position allowing to deliver to the second stage 7 of the heating assembly a variable direct electric voltage as a complement to the principal voltage delivered to the first heating stage 5.

To this end, the temperature sensors 27 a, 27 b, 27 c, 27 d, the control unit 25 and the contactor 29 constitute means for delivering a complementary voltage to the principal voltage supplying the second stage of the heating assembly.

The complementary voltage supply of the second heating stage 7 typically intervenes during specific phases of a flight, such as phases of ascent or descent of the airplane.

By way of example, during the ascent phases, the second heating stage 7 of the heater 3 d is supplied with complementary voltage, while during the descent phases, the second heating stage of the heater 3 b will be supplied with complementary voltage. Furthermore, while crossing dense clouds, the second heating stage of the heaters 3 b and 3 d are supplied with complementary voltage.

More generally, the flight phases requiring the activation of the second stage of the heating assembly are those which require electric power such that the only power provided to the first stage of the heating assembly is insufficient for maintaining a temperature which prevents the formation of frost or of ice or allowing the de-icing. Thus, the power supply of the second heating stage is not limited to the sole phases of ascent and descent of the airplane, but may also intervene when the airplane is in cruise power, for example in the case where a particular event suddenly modifies the temperature of the nacelle air inlet lip.

In other words, the second heating stage is locally and temporarily powered when the more heating capacities of the first stage of the heaters are attained.

By providing voltage to the second stage during particular events of the flight phase of the airplane, the energy consumption of the de-icing device is reduced. Furthermore, the voltage delivered to each stage is adapted for maintaining the temperature in the air inlet lip constant regardless of the outer temperature conditions.

In addition, with respect to the prior art, a single power supply source allows to supply several heating stages independently from one another thanks to a single contactor added to the de-icing circuit.

Reference is now made to FIGS. 5 and 6 illustrating the de-icing device according to a second form of the present disclosure.

The electric power supply source is constituted of a dedicated generator 31 mounted on a transmission box mechanically coupled to an engine turbine shaft.

The generator 31 delivers a voltage to the first stage of the heating assembly via a cable 32 and to a de-icing circuit (“NAI”) 33, said voltage having a variable frequency according to the rotational speed of the turbine shaft.

The de-icing circuit 33 receives at the outlet a cable 35 supplying with voltage the second heating stage of the heating assembly.

The de-icing circuit 33 comprises a control unit 37 connected to the temperature sensors 27 a, 27 b, 27 c, 27 d.

According to the present disclosure, the de-icing circuit 33 comprises a single contactor 39 connected to the cable 35 in connection with the second heating stage. The contactor 39 is activated or inhibited thanks to the control unit 37 at the outlet of which it is connected. By way of example, the contactor may be constituted by an electric or electromechanical switch.

The operation of the de-icing/anti-icing device according to the second form of the present disclosure is similar to the operation of the first form, except that the de-icing/anti-icing circuit no longer performs the conversion of the voltage delivered by the electric power supply source.

The generator 31 supplies with voltage the first heating stage 5 of the heating assembly and the de-icing circuit 33.

The temperature sensors 27 a, 27 b, 27 c, 27 d return the temperature values identified at each heater 3 a, 3 b, 3 c and 3 d to the control unit 37.

The control unit 37 therefore adapts the value of the output voltage supplying the first heating stage so as to maintain the temperature of the lip constant regardless of the outer climatic conditions.

The contactor 39 is in an inhibited position, a position according to which no voltage is delivered to the second stage of the heating assembly.

When the voltage delivered by the generator is insufficient for maintaining the temperature of the nacelle air inlet lip constant, the control unit 37 activates the passage of the contactor 39 from inhibited position thereof to a closed position, a position allowing to deliver to the second stage 7 of the heating assembly a variable electric voltage complementary to the principal voltage delivered to the first heating stage 5.

As before, the temperature sensors 27 a, 27 b, 27 c, 27 d, the control unit 37 and the contactor 39 constitute means for delivering a voltage complementary to the principal voltage supplying the second stage of the heating assembly, the supply with complementary voltage of the second stage typically preferably intervening during specific phases of a flight, such as phases of ascent or of descent of the airplane.

Thanks to the present disclosure, by providing a network of several stages of heating mats by a single electric power supply source, the de-icing/anti-icing device is simplified with respect to the solutions of the prior art.

In fact, the single electric power supply source supplies a first heating stage, the one closest to the area in contact with the flowing air. When climatic conditions require an additional heating power, the de-icing device according to the present disclosure supplies with electric energy a second heating stage, superimposed to the first, and farther away from the area in contact with the flowing air. The second stage, in a way, acts as a thermal reinforcement occasionally activated by the same electric power source as that which supplies the first stage of the heater.

The contactor, directly provided in the de-icing/anti-icing circuit, controls power supply to the second stage of the heating assembly according to the identified temperature of the nacelle element to be protected from frost, in such a manner that the temperature remains constant regardless of the outer climatic conditions.

Furthermore, the de-icing device according to the present disclosure improves the safety of the de-icing device so that the availability of the heating assembly is increased. In fact, in case of dysfunction of the first stage of the heating assembly, the control unit activates the contactor from the inhibited position thereof to the closed position thereof, so as to supply with voltage the second stage. This allows providing the operation of the de-icing device in the event of failure during flight of the primary heating element.

The present disclosure is not limited to the sole forms of this de-icing/anti-icing device, described above only by way of illustrating examples, but it encompasses all variants involving the technical equivalents of the described means as well as their combinations if these should fall within the scope of the present disclosure. 

What is claimed is:
 1. An electric de-icing/anti-icing device for a turbojet engine/turboprop nacelle element, comprising: a heating assembly comprising first and second heating stages disposed in the nacelle element to be protected from frost; an electric energy power supply circuit delivering a principal voltage to the first heating stage, and comprising: an electric power supply source, a de-icing/anti-icing circuit connected to the heating assembly and supplied with voltage by said electric power supply source; and means for delivering a complementary voltage to the second heating stage of the heating assembly.
 2. The electric de-icing/anti-icing device according to claim 1, wherein the means for delivering the complementary voltage comprises: at least one temperature sensor positioned in the nacelle element to be protected from frost; at least one contactor integrated to the de-icing/anti-icing circuit and also connected at an inlet to the electric power supply source and at an outlet to the second heating stage of the heating assembly; and at least one control unit connected to the temperature sensor and to the contactor, adapted to alternatively control a passage of the contactor between an inhibited position in which the second heating stage is not supplied with a voltage and a closed position in which the second heating stage is supplied with a voltage.
 3. The electric de-icing/anti-icing device according to claim 2, wherein the control unit is integrated to the de-icing/anti-icing circuit.
 4. The de-icing/anti-icing device according to claim 1, wherein the electric power supply source is delivered by an airplane electric network.
 5. The de-icing/anti-icing device according to claim 2, further comprising: a power conversion stage supplied with alternating voltage by an airplane electric network and connected to the control unit, said power conversion stage being adapted to convert the alternating voltage delivered by the airplane electric network to variable direct voltage; and a contactor, an inlet thereof connected to an outlet of a power conversion stage and the outlet connected to the second heating stage, said contactor being controlled by the control unit.
 6. The de-icing/anti-icing device according to claim 1, wherein the electric power supply source is constituted by an electric generator.
 7. The de-icing/anti-icing device according to claim 6, wherein the electric generator is further connected to the first heating stage of the heating assembly, and the de-icing/anti-icing circuit is constituted by a contactor of which an inlet is connected to said electric generator, and an outlet of the contactor connected to the second heating stage of the heating assembly, and said contactor being controlled by the control unit.
 8. The de-icing/anti-icing device according to claim 1, wherein the heating assembly comprises four heaters distributed on a periphery of the nacelle element to be protected from frost.
 9. A nacelle for a turbojet engine/turboprop comprising the de-icing/anti-icing device according to claim 1, wherein the heating assembly is integrated to an air inlet lip of the nacelle.
 10. A method of de-icing/anti-icing of a nacelle element for a turbojet engine or turboprop, said nacelle element comprising a de-icing/anti-icing device according to claim 1, said method comprising: identifying a temperature of a nacelle element; delivering to the first heating stage of the heating assembly a variable principal voltage according to the identified temperature; delivering to the second heating stage of the heating assembly a complementary voltage when a value of the identified temperature of the nacelle element to be protected from frost is lower than a predetermined temperature value.
 11. A method of de-icing/anti-icing of an aircraft element, said aircraft element comprising the de-icing/anti-icing device according to claim 1, said method comprising: identifying a temperature of an aircraft element; delivering to the first heating stage of the heating assembly a variable principal voltage according to the identified temperature; delivering to the second heating stage of the heating assembly a complementary voltage when a value of the temperature of the aircraft element to be protected from frost is lower than a predetermined temperature value. 